Binaural recording is a method of recording sound that uses two microphones, arranged with the intent to create a 3-D stereo sound sensation for the listener of actually being in the room with the performers or instruments. This effect is often created using a technique known as “Dummy head recording”, wherein a mannequin head is outfitted with a microphone in each ear. Binaural recording is intended for replay using headphones and will not translate properly over stereo speakers.
Headphones (or earpieces) are commonly used with mobile devices. To improve the listening experience, active noise cancellation (ANC) methods are commonly used in these headphones. ANC methods typically require a microphone on each side of the stereo headset and a 5-pole connector to the device.
Given that these headphones have microphones built into the earphone casings, these headsets may be used for hands-free speech communication as well, removing the need for an extra microphone. However, since the microphones are on the earphones-casings, and on each side of the head (when in use), the speech signal these microphones pick up are attenuated (especially in the higher frequencies) due to the shadowing of the head. Thus some signal processing is usually required to compensate for this attenuation.
Another aspect to consider when using these headphones for communication is the impact of environmental (background) noise. This noise is detrimental to the intelligibility and the comfort of the communication, requiring some means of noise-suppression to suppress the environmental noise.